Amgen Inc.
Drug delivery device having minimized risk of component fracture upon impact events

Abstract:

A drug delivery device includes a reservoir, a drug delivery member in fluid communication with the reservoir, and a plunger disposed in and moveable relative to the reservoir. A plunger rod has a mass M.sub.P and is movable from (i) a first position, where the distal end of the plunger rod is spaced apart from the plunger to (ii) a second position, where the distal end of the plunger rod contacts the plunger. A drive mechanism is coupled to the proximal end of the plunger rod and is configured to deliver a drive force F.sub.D to move the plunger rod from the first position to the second position. A ratio of the mass of the plunger rod to the drive force of the drive mechanism (M.sub.P/F.sub.D) is in a range of approximately a value greater than 0 kg/kgf to approximately 0.05 kg/kgf.